Hoornweg is there to give the group a good steady rhythm. He was present in each of Joshua's world records. He will probably lead the first 1600m. Then Kissa will take him further, he hasn't ever focused on the track but he is a very capable athlete, although i agree 3000m might be a stretch for him. However through 2400m should be within his grasp.
Then it's onto Ramsden to get Joshua through 3000m. Ramsden recently did a TT in 7:39 where he was barely beaten by Stewart McSweyn by 1". He is in the shape of his life and most probably will be able to get Joshua through 3000m in 7:37 as planned.